The inky sea creature preserved in a specimen jar

An unusual sea creature lurks within an old specimen jar in the Winsor and Newton archives: a raw sample of a cuttlefish ink sac. But just what was it used for? And how did it end up here? 

The journey from the sea to sepia is a testament to the unexpected wonders of nature. The common cuttlefish releases ink when it is fleeing from a predator or protecting its eggs. The Ancient Greeks discovered that this ink could be useful. They came up with a process of drying the ink sac and then grinding it into a powder. The colour that it produced was sepia. The name originates from the Ancient Greek term for cuttlefish, sepia officinalis.  

Later, during the 1700s, sepia ink was used to write script on paper. By the 1800s it was being used for watercolour painting. Though natural sepia was mostly permanent, when it is mixed with carbon and umber it gives artists permanent, long-term results. 

Our archival sample illustrates how colourmen purchased sepia. Fishermen would carefully remove the ink sacs intact and lay them out on rocks to dry and become solid. They would then be sold to colourmen like Winsor & Newton who ground into ink and watercolour pigments to be used by artists.  

So, the next time you see a sepia-toned painting, it just might be made of ink from a humble cuttlefish.